Well fluid formulation and method

ABSTRACT

A method for improving bonding and sealing in a well, comprising providing a wellbore, providing a pipe, coating an outside surface of the pipe with an adhesive thermoplastic resin, running the coated pipe into the wellbore, and causing the temperature of said wellbore to increase to a temperature greater than a melting temperature of said adhesive thermoplastic resin.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/807,771 filed Jul. 19, 2006, which is incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to improved well fluid formulations andmethods of utilizing such formulations.

BACKGROUND OF THE INVENTION

The practice of cementing wells to provide isolation between exposedformations along a wellbore has been used in the drilling industry for acentury. It is estimated over a billion sacks of cement have been usedfor this purpose. The process of primary and remedial cementing has beenextensively studied over the past six decades and many improvements havebeen made which increase the effectiveness of the process in order toachieve zonal isolation. However, there are several fundamentallimitations in the current state of the art of cementing wells thatlimit success in providing the most effective zonal isolation.

One limitation is that it is difficult to completely remove or displaceall the drilling fluid (or other fluid) in the wellbore with cementslurry when placing the cement during the primary cementing process.Another limitation is that the cement does not bond (or adhere)satisfactorily to casing surfaces and drilling fluid filter cake orresidue. Furthermore, changes in the stress state of the wellbore duringcompletion of drilling and throughout the productive life of the wellcan damage the cement bond/seal to cement and formation. These changesin the stress state of the wellbore may be the result of thermal changes(temperature) or pressure changes (for example, displacing a heavy fluidin the casing with a lighter fluid during completion of the well oradditional deepening of the well, or changes in formation pressures orchanges in annular pressures).

It is known in the art to include additives to prevent fluid loss incement compositions. U.S. Pat. No. 4,716,965 discloses an improvement ina cementing process for preventing fluid migration between the casingand cement in a situation where a casing is suspended within a well anda slurry of cement is flowed into the space between the casing and theborehole wall and allowed to harden, comprising: surrounding at leastone portion of the outer surface of the casing with a self-supportingsheath of an elastomeric foam comprising alternately arranged layers ofa closed cell polyurethane foam and a closed cell polyethylene foamwhich, together, are capable of remaining resilient and retaining thestructural integrity of the sheath after compression by the hydrostaticpressure of a slurry of cement; inflowing the cement slurry into theborehole around the casing and sheath; and allowing the cement to hardenwith the resilient tendency toward expansion of the elastomeric foamensuring good adhesion of the sheath to both the casing and cement.

U.S. Pat. No. 5,151,131 discloses a liquid fluid loss control additivefor an aqueous well cement composition, said additive including anorganophilic clay suspending agent present in an amount in the range offrom 0.5 to about 8 percent by weight of said liquid hydrocarbon, asurfactant present in said additive in an amount in the range of fromabout 0.5 to about 8 percent by weight, and at least one hydrophilicpolymer present in an amount in the range of from about 40 to about 150percent by weight of said liquid hydrocarbon.

U.S. Pat. No. 5,458,195 discloses an improved cementious compositionwhich can include drilling fluid as a component and methods of cementingwells utilizing such compositions, said cementious composition includinga drilling fluid present in an amount up to about 70% by volume, and ahardenable resinous material selected from the group consisting ofvernonia oil, epoxidized linseed oil or soy oil, an acrylic resinousmaterial, an epoxy resinous material, a phenolic resinous material andmixtures of said resinous materials present in said composition in anamount in the range of from about 1% to about 50% by weight of saidcementious material or materials; and water present in said compositionin an amount in the range of from about 20% to about 175% by weight ofsaid cementious material.

In the current state of the art there are limitations on theeffectiveness of cement slurries and drilling fluids that result in lessthan desirable adherence of cement to casing surfaces and drilling fluidcake or residue. Many of these problems could be effectively addressedby cementious compositions characterized by improved ductility and bycement slurries and drilling fluid formulations that afford betterbonding, sealing and adhesion.

SUMMARY OF THE INVENTION

The present inventions include a method for improving bonding andsealing in a well, comprising providing a wellbore, providing a pipe,coating an outside surface of the pipe with an adhesive thermoplasticresin incorporated into a well fluid, running the coated pipe into thewellbore, and causing the temperature of said wellbore to increase to atemperature greater than a melting temperature of said adhesivethermoplastic resin.

DETAILED DESCRIPTION

Adhesive thermoplastic materials, commonly known as hot melt glues orhot melt adhesives, may be incorporated into drilling fluids, spottingfluids, and cement slurries, and applied to casings, equipment, andhardware to improve the sealing and bonding of the components of a well.Adhesive thermoplastic materials are commonly used in household hot meltglue adhesives and in tough resilient, non-abrasive elastomers andsealants. In the present invention adhesive thermoplastic materials areselected based upon melting point, thermal stability, materialproperties at well operating temperatures, well geothermal statictemperature, circulating temperature of the wellbore, and zonalisolation requirements for the well.

Of particular interest are adhesive thermoplastic polymers or resinsthat have reactive chemical groups which promote adhesion and can reactwith components of the cement, unremoved drilling fluid, formation, andwell casings to form a seal, repair a seal destroyed by stresses in thewell, alter the material properties of the cement or any remainingdrilling fluids in the wellbore, and to make the cement or otherremaining fluids more resistant to damage under the stresses of welloperating conditions.

The adhesive thermoplastic polymers or resins can be used to formsealants with drilling fluids and cement slurries; to alter the materialproperties of cements, in particular increasing ductility; to sealleaking connections in casing strings; to seal weak or highly permeableformations, and to heal loss circulation problems; or to sealmicroannuli between cement and casing(s).

Examples of suitable adhesive thermoplastics for use in the presentinvention include certain acrylic acid copolymers, and ionomers andsalts thereof. Suitable copolymers include, but are not limited to,ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers,ethylene-vinyl acetate copolymers, ethylene-vinylphosphonic acidcopolymers and ionomers or salts of acid forms of acidic copolymers. Byionomer is meant organometal compositions having a metal attached to orinterlocking (crosslinking) a polymer chain. Ionomers are prepared byneutralization of the carboxylic acid group of the copolymers, orpartial neutralization with metal ions. Suitable salts include, but arenot limited to salts of Group IA, IIA, or IIB of the Periodic Table.Specific examples include, but are not limited to sodium, calcium,magnesium, and zinc, or combinations thereof. Blends of materials mayalso be used to vary properties and performance of the materials to meetperformance conditions.

Ionomers containing zinc, calcium, and magnesium are available under thetradename AcLyn® from Honeywell International, Inc. Single valentionomers containing sodium, as well as zinc ionomers are availablecommercially under the tradename LOTEK from Exxon Mobil.

In addition to copolymers, homopolymers of high molecular weight acrylicacid (polyacrylic acid), methacrylic acid (polymethacrylic acid), vinylphosphonic (polyvinyl phosphonic) or blended compounds such aspolyethylene blended with acrylic, methacrylic, polyacrylic,polymethacrylic, vinyl phosphonic, or polyvinylphosphonic acids orionomers thereof may form suitable sealants which fulfill the functionsrequired.

Copolymers and ionomers are commercially available from a variety ofsources. Ethylene acrylic acid copolymers are available from Honeywell(Allied Signal) under the product name A-C Copolymers®, from Dow underthe general product name PRIMACOR®, and from DuPont under the generalproduct name NUCREL®.

Copolymers and ionomers are generally supplied as pellets, beads,powders, granules, or prills. Sizes can be selected for particularconditions and the treating fluid may contain a mix of sizes forenhanced performance. Aqueous dispersions of the products may also beused in some situations.

In some applications it may be advantageous to utilize the copolymers inthe form of a liquid dispersion. Liquid dispersions can also be used inthe treatment mixture for suspension, variation of reactivity over arange of temperatures, and for small bridging particles. Heating up thecopolymers and dropping them into solvent under high sheer makesdispersions. This has the effect of increasing the copolymer surfacearea by breaking up the copolymer and forming vast numbers of smallerparticles, each having readily available reactive groups. The use ofdispersions can provide fast reaction times because more —COOH groupsare available for reaction. The particles in dispersion may be in therange of 0.03 microns to 0.3 microns. Suitable ethylene acrylic aciddispersions are available commercially under the tradename Michem® Prime4983R, 4983-40R, and 4990R from Michelman, Inc.

The invention is not intended to be limited to particular cementiousmaterials. Suitable cement compositions include, for example, but arenot limited to hydraulic cements, high alumina cement, slag, fly ash,condensed silica fume with lime, gypsum cement, and mixtures ofcementious materials. Examples of hydraulic cement include Portlandcements of the various types identified in API Specification forMaterials and Testing for Well Cements, API Spec. 10 of the AmericanPetroleum Institute, which is incorporated herein by reference.

The drilling fluid or mud can be either a conventional drilling fluid,i.e., one not containing a cementious material, or it can be one alreadycontaining a cementitious material in a relatively small amount. Thedrilling fluid can be either a water-based fluid or an oil-based fluid.The term ‘water-based fluid’ is intended to encompass both fresh watermuds and salt water-containing muds, whether made from seawater orbrine, and other muds having water as the continuous phase includingoil-in-water emulsions. In any event drilling fluid will generallycontain at least one additive such as viscosifiers, thinners, dissolvedsalts, solids from the drilled formations, solid weighting agents toincrease the fluid density, formation stabilizers to inhibit deleteriousinteraction between the drilling fluid and geologic formations, andadditives to improve the lubricity of the drilling fluid. The teachingof U.S. Pat. No. 5,325,922 is incorporated by reference herein in theentirety.

The adhesive thermoplastic resins can also be incorporated into spottingfluids. Suitable spotting fluids should have a good lubricating effectand the ability to ensure good oil wetability of the surfaces of thedrill pipe and of the walls of wells coming into contact with the drillpipe. Spotting fluids known in the art typically comprise hydrocarbonmixtures, often based on diesel oils or mineral oils. Emulsifiers andsurfactants are typically added. The invention is not intended to belimited to any particular spotting fluids and those skilled in the artwill see numerous possibilities.

A catalyst or initiator is useful in the application of the presentinvention. The use of catalysts and initiators is known in the art andthe invention is not intended to be limited to any particular type.Suitable catalysts may include, for example, but not be limited to, freeradical initiating catalysts or catalyst systems. Such catalysts may beorganic peroxy-compounds such as benzoyl peroxide, dibenzoyl peroxide,diacetyl peroxide, di-t-butyl peroxide, cumyl peroxide, dicumylperoxide, dilauryl peroxide, t-butyl hydroperoxide, methyl ketoneperoxide, acetylacetone peroxide, methylethyl ketone peroxide,dibutylperoxyl cyclohexane, di (2,4-dichlorobenzoyl) peroxide,diisobutyl peroxide, t-butyl perbenzoate, and t-butyl peracetate. Thecatalyst may be employed in total amounts from about 0.01 to about 50weight percent based upon the weight of the polymerizable monomer. Othersuitable catalysts may include strong acid catalysts such as sulfonic,or organic or mineral acids, such as, for example formic, boric,phosphoric, oxalic and acid salts of hexamethylenetetramine.

In some instances, it may be desirable to use a material which functionsas a retarder along with the catalyst or activator due to the need forother effects brought about by the retarder. For instance, chromiumlignosulfonate may be used as a thinner along with the activator eventhough it also functions as a retarder. Other suitable thinners includechrome-free lignosulfonate, lignite, sulfonated lignite, sulfonatedstyrene maleic-anhydride, sulfomethylated humic acid, naphthalenesulfonate, a blend of polyacrylate and polymethacrylate, anacrylamideacrylic acid copolymer, a phenol sulfonate, a naphthalenesulfonate, dodecylbenzene sulfonate, and mixtures thereof.

The selection of the proper adhesive thermoplastic material to improvebonding and sealing in well fluid in a particular situation requires twoconsiderations. First, the material may be selected because it meltsbetween the circulating temperature of the wellbore and the undisturbedgeothermal temperature of the well. The material is incorporated intothe cement slurry, drilling fluid, or spotting fluid, or on the outsideof the casing string, and placed in the wellbore at a temperature lessthan the static or undisturbed geothermal temperature. After placement,the wellbore will heat up, melting the material and allowing it to fillunsealed areas and/or react to adhere to surfaces or to form an ionomerwith metallic ions in the cement, drilling fluid and/or formation.

Secondly, for thermal recovery projects, or deep water wells where thewell temperature of the formation is lower than the operatingtemperature of the well, a material may be selected because it will meltat a temperature between the undisturbed geothermal temperature of thewell and the operating temperature of the well (or at/slightly below theoperating temperature of the well). Hot injectants or products may beused to heat the well or parts of the well to temperatures above thenatural, undisturbed geothermal static temperature of the formation.Three examples of this are:

a. Steam injection wells—high temperature (250-650° F. or 120-350° C.)steam is injected through a well into a formation to mobilize thick oilor bitumen. The steam temperatures are greater than the naturaltemperatures of the formation.

b. Thermal Conduction Wells—a wellbore is heated above its naturalformation temperature by conduction of heat from a heated casing ornon-cased wellbore. The casing or wellbore may be heated by electricalresistive heating, hot gas or steam circulation inside the casing orwellbore or downhole combustion.

c. Deepwater or cold environment wells—production of fluids from aformation deeper in the well transfers heat from deeper formations upthrough the entire well as production occurs. In arctic wells, theshallow soil temperature may be below freezing (32° F. or 0° C.) whiletemperatures at the bottom of the wellbore may exceed the boiling pointof water (212° F. or 100° C.). As warm fluids are produced, the shallowsediments warm up. Similarly, in deep water wells the temperature at thesea floor may be 40° F. (4° C.), but during production, the temperaturein the shallow sediments just below the seafloor may be warmed to 200°F. (90° C.) depending upon production rate, time and temperatures of theproducing formation. Finally, deep wells with high temperatures may heatthe entire casing of the well to temperatures approaching thetemperature of the producing formations. In some gas wells, for example,the ambient temperature around the wellhead is between 60° F. and 100°F. (15° C. and 40° C.) depending upon the season. However, the wellheadtemperature during production is between 250° F. and 325° F. (120° C.and 160° C.) depending upon well depth, production rate, and time.

The well fluids modified with adhesive thermoplastic resins are helpfulin isolation of exposed formations in the wellbore, sealing leaksbetween cement and borehole wall, cement and casing(s), or leaks incasing connections. In the first embodiment of the invention theadhesive thermoplastic materials are added to drilling fluids to formwell fluids that also seal. Any drilling fluid not removed by the cementduring cementing would form a sealant to prevent flow through channelsresulting from the unremoved drilling fluid.

In another embodiment the thermoplastic materials are added to thecement slurry used to cement a well. The thermoplastic melts afterplacement, seals stress cracks in the cement, improves bond to theformation and well casings, and seals microannulus between cement andcasing or cement and formation.

In another embodiment the adhesive thermoplastic materials are added todrilling fluids or spotting fluids placed in the wellbore prior torunning casing and/or cementing. Any drilling fluid not removed by thecement during cementing would form a sealant to prevent flow throughchannels resulting from the unremoved drilling fluid.

In s another embodiment the adhesive thermoplastic material is appliedon the outside of the casing string or, for example, on the equipment,and hardware. A coating of adhesive thermoplastic resin can be sprayedonto the outside of the pipe(s) prior to placement in the well. Thethermoplastic resin may be mixed with a compound such as toluene to forma paste that can be spread onto the equipment. The adhesivethermoplastic may also be applied as sheets or bands around the pipeprior to installation in the well. Hardware, such as, for example,spacers, centralizers, banding rings, etc. may be sprayed with, coatedwith, or made in part of adhesive thermoplastic resin and incorporatedinto the casing(s) prior to running into the well. Connections of thecasing or sealing surfaces of wellhead or downhole equipment may besprayed with, coated with, or made in part of adhesive thermoplasticmaterials prior to installation in the well or installation of casings.

Those of skill in the art will appreciate that many modifications andvariations are possible in terms of the disclosed embodiments,configurations, materials, and methods without departing from theirspirit and scope. Accordingly, the scope of the claims appendedhereafter and their functional equivalents should not be limited byparticular embodiments described and illustrated herein, as these aremerely exemplary in nature and elements described separately may beoptionally combined.

The following examples will serve to illustrate the invention disclosedherein. The examples are intended only as a means of illustration andshould not be construed as limiting the scope of the invention in anyway. Those skilled in the art will recognize many variations that may bemade without departing from the spirit of the disclosed invention.

EXAMPLE 1 Compatibility with Cement

A cement slurry was prepared using 800 grams API Class H PortlandCement, 40 grams ACLyn 540, 4 grams high temperature lignosulfonateretarder, and 320 grams distilled water. The slurry was sheared in aconsistometer while heating from 24° C. (75° F.) to 102° C. (215° F.) in44 minutes. Pressure on the slurry was increased from 68.9 bar (1000psi) to 965.3 bar (14,000 psi) during heating. The slurry was sheareduntil the cement set. No premature gellation was observed during thetest and the resulting mass was a cohesive solid.

EXAMPLE 2 Increasing Cement Ductility

400 grams of API Class H Portland Cement and 400 grams ACLyn 580 werecombined with 4 grams of high temperature lignosulfonate retarder and320 grams distilled water. The slurry was sheared in a consistometerwhile heating from 24° C. (75° F.) to 149° C. (300° F.) in 60 minutes.Pressure on the slurry was increased from 68.9 bar (1000 psi) to 965.3bar (14,000 psi) during heating. The slurry was sheared until the cementset. The resulting mass was soft and flexible and not set as firmly asthe mixture of Example 1. A portion of the copolymer separated near thetop of the slurry and set into a strong, flexible mass havingflexibility of a plastic card, such as a credit card. Microscopicexamination of the flexible mass showed no permeability in the matrixand the cement and copolymer combined to form a composite,fiber-reinforced matrix.

EXAMPLE 3 Improving Interfacial Sealing Between Cement and Pipe

A cement slurry was prepared using 800 grams API Class H PortlandCement, 80 grams ACLyn 580, 4 grams high temperature lignosulfonateretarder, and 320 grams distilled water. The slurry was placed in aU-shaped pipe and placed in an oven set to a temperature below themelting point of the ACLyn 580 copolymer. The cement was allowed to setundisturbed at a temperature below the melting point of the ACLyn 580copolymer. After the cement set, a differential pressure of 50 psi (3.45bar) was created with nitrogen gas across the two legs of the U-tube.Nitrogen gas leaked between the two legs of the U-tube at a rate inexcess of 1×10⁻³ cc/psi-minute.

The temperature of the oven was increased to a temperature 10° F. (5.55°C.) below the melting temperature of the ACLyn 580 copolymer and adifferential pressure of 50 psi (3.45 bar) was created with nitrogen gasacross the two legs of the U-tube. Nitrogen gas leaked between the twolegs of the U-tube at a rate in excess of 5×10⁻³ cc/psi-minute. Theincreased leakage rate of gas was believed to be due to the expansion ofthe metal U-tube with temperature.

The temperature of the oven was increased to a temperature 10° F. (5.55°C.) above the melting temperature of the ACLyn 580 copolymer and adifferential pressure of 100 psi (6.9 bar) were created with nitrogengas across the two legs of the U-tube. Nitrogen gas leaked between thetwo legs of the U-tube at a rate 3.5×10⁻⁴ cc/psi-minute. The decreasedleakage rate of gas was believed to be due to the melting and reactionof the copolymer with the metal U-tube.

The temperature of the oven was increased to a temperature 50° F. (27.8°C.) above the melting temperature of the ACLyn 580 copolymer and adifferential pressure of 500 psi (34.45 bar) were created with nitrogengas across the two legs of the U-tube. Nitrogen gas leaked between thetwo legs of the U-tube at a rate 2.2×10⁻⁵ cc/psi-minute. The decreasedleakage rate of gas was believed to be due to the melting and reactionof the copolymer with the metal U-tube.

EXAMPLE 4 Incorporation into Pipe

A paste of ACLyn 580 and toluene was created by heating toluene, addingACLyn 580, and stirring until a thick, translucent paste was formed.This paste was applied in a 2 inch wide band, approximately 1/16 inchthick to the inside of one leg of a U-tube. The paste was allowed tocool and then the U-tube was heated to 150° F. (66° C.) to evaporateexcess solvent.

A cement slurry prepared with 800 grams API Class H Portland Cement and320 grams distilled water was place in the U-tube. The U-tube was placedin an oven and both legs pressurized to 2000 psi (138 bar). The oven washeated to 125° F. ( ) and the cement was allowed to set. After thecement set, a differential pressure of 50 psi (3.45 bar) was createdwith nitrogen gas across the two legs of the U-tube. Nitrogen gas leakedbetween the two legs of the U-tube at a rate in excess of 1×10⁻³cc/psi-minute

The temperature of the oven was increased to a temperature 50° F. (27.8°C.) above the melting temperature of the ACLyn 580 copolymer and adifferential pressure of 500 psi (34.5 bar) were created with nitrogengas across the two legs of the U-tube. No nitrogen gas leaked betweenthe two legs of the U-tube at this differential pressure. Thedifferential pressure was increased to 1000 psi and no leakage ofnitrogen was measured over a 30-minute period. The differential pressurewas increased to 1500 psi (103 bar) and no leakage of nitrogen wasmeasured over a 60-minute period.

Other embodiments of the invention will be apparent to those skilled inthe art from a consideration of this specification or from practice ofthe invention disclosed.

EXAMPLE 5 Effect on Poisson's Ratio and Young's Modulus

A cement slurry was prepared using varying amounts of ACLyn 580. Themixture was cured at 80° F. and 230° F. (27° C. and 110° C.) and aconfining pressure of 3000 psi (207 bar) was applied. Young's Modulusand Poisson's Ratio were determined from data between 20-60% compressivestrength. Table 1 shows the results. Table 2 shows the results in SIunits. The test revealed that increasing the amount of the copolymermakes the cement more ductile. When cured at a temperature below 80° F.(27° C.), the copolymer is an elactic filler. However, when cured attemperatures above the melting point of the copolymer, an ionomer isformed by the reaction of the functional groups on the copolymer withmono-, di-, and tr-valent alkali and transitional metal salts in thecement. This results in a more rubbery material with a much higherPoisson's ratio. TABLE 1 AC-540A Sample Curing Compressive ElasticCopolymer Temperature Strength Poisson Modulus % wt ° F. psi Ratio psi 0  80 F. 5,519 0.1359 1,200,000 10   80 F. 6,240 0.0923 414,000 20   80F. 4,639 0.0661 210,000 30   80 F. 3,441 0.2403 114,000 0 230° F. 5,7430.1113 1,250,000 10 230° F. 5,032 0.3224 936,000 20 230° F. 3,423 0.4677224,000 30 230° F. 2,838 0.2948 154,000

TABLE 2 AC-540A Sample Curing Compressive Elastic Copolymer TemperatureStrength Poisson Modulus % wt ° C. bar Ratio bar 0 27 381 0.1359 82,74010 27 430 0.0923 28,540 20 27 320 0.0661 14,480 30 27 237 0.2403 7,860 0110 396 0.1113 86,180 10 110 347 0.3224 64,530 20 110 236 0.4677 15,54030 110 196 0.2948 10,620

1. A well fluid formulation comprising a well fluid and at least oneadhesive thermoplastic resin.
 2. The well fluid formulation of claim 1wherein the well fluid is selected from the group consisting of drillingfluid, spotting fluid, and cement slurry.
 3. The well fluid formulationof claim 2 wherein the adhesive thermoplastic resin is a copolymerselected from the group consisting of ethylene-acrylic acid copolymers,ethylene-methacrylic acid copolymers, ethylene-vinyl acetate copolymers,ethylene-vinylphosphonic acid copolymers, ionomers or salts of acidforms of acidic copolymers, and combinations thereof.
 4. The well fluidformulation of claim 3 wherein the ionomer or salt is of a metalselected the group consisting of from sodium, calcium, magnesium, andzinc.
 5. The well fluid formulation of claim 2 wherein the adhesivethermoplastic resin is a homopolymer selected from the group consistingof high molecular weight acrylic acid, methacrylic acid, vinylphosphonic acid, and combinations thereof.
 6. The well fluid formulationof claim 5 wherein the adhesive thermoplastic is selected from anionomer or salt of at least one homopolymer or a combination thereof. 7.The well fluid formulation of claim 6 wherein the ionomer or salt is ofa metal selected from sodium, calcium, magnesium, and zinc.
 8. The wellfluid formulation of claim 2 further comprising the adhesivethermoplastic resin is selected from a blend of polyethylene with acompound selected from the group consisting of acrylic, methacrylic,polyacrylic, polymethacrylic, vinyl phosphonic, polyvinylphosphonicacids, and ionomers and salts thereof, and combinations thereof.
 9. Thewell fluid formulation of claim 2 further comprising the adhesivethermoplastic material is in a form selected from the group consistingof powders, prills, pellets, pills, and dispersions.
 10. A method forimproving bonding and sealing in a well, comprising: a. providing awellbore; b. providing a pipe; c. coating an outside surface of the pipewith an adhesive thermoplastic; d. running the coated pipe into thewellbore; and e. causing the temperature of said wellbore to increase toa temperature greater than a melting temperature of said adhesivethermoplastic resin.
 11. The method of claim 10 further comprisingheating the well with hot injectants.
 12. The method of claim 11 whereinthe adhesive thermoplastic material melts between the circulatingtemperature of the wellbore and the undisturbed geothermal temperatureof the well.
 13. The method of claim 11 wherein the adhesivethermoplastic resin melts between the undisturbed geothermal temperatureof the well and the operating temperature of the well.
 14. The method ofclaim 11 wherein the adhesive thermoplastic resin is a copolymerselected from the group consisting of ethylene-acrylic acid copolymers,ethylene-methacrylic acid copolymers, ethylene-vinyl acetate copolymers,ethylene-vinylphosphonic acid copolymers, ionomers or salts of acidforms of acidic copolymers, and combinations thereof.
 15. The method ofclaim 14 wherein the ionomer or salt is of a metal selected from sodium,calcium, magnesium, and zinc.
 16. The method of claim 11 wherein theadhesive thermoplastic resin is a homopolymer selected from the groupconsisting of high molecular weight acrylic acid, methacrylic acid,vinyl phosphonic acid, ionomers or salts of acid forms thereof, andcombinations thereof.
 17. The method of claim 16 wherein the ionomer orsalt is of a metal selected from sodium, calcium, magnesium, and zinc.18. The method of claim 11 further comprising the adhesive thermoplasticresin is selected from a blend of polyethylene with a compound selectedfrom the group consisting of acrylic, methacrylic, polyacrylic,polymethacrylic, vinyl phosphonic, polyvinylphosphonic acids, andionomers and salts thereof, and combinations thereof.
 19. The method ofclaim 18 further comprising the adhesive thermoplastic material is in aform selected from the group consisting of powders, prills, pellets,pills, and dispersions.